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NASA NTRSDate not supplied

Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction

NASA’s Artemis Program seeks to establish a long-term presence on the Moon to enable scientific exploration and expand the cis-lunar economy by utilizing lunar resources through public-private and international partnerships. Over the next decades, a lunar spaceport will need to be established to provide the services and facilities that are necessary to achieve this goal. Robotic construction technologies using in-situ materials must be developed to build up enabling infrastructure such as launch/landing pads, blast protection, power/communications infrastructure, improved roads, improved operational surfaces, and radiation protection shelters. Kennedy Space Center’s Granular Mechanics and Regolith Operations laboratory at Swamp Works has partnered with SpaceFactory and LERA Consulting Structural Engineers to develop the architectural and structural design of an unpressurized lunar shelter. The shelter, called Lunar Infrastructure Asset (LINA), is designed to support 2.3 m of regolith overburden to protect astronauts and surface assets from radiation, meteoroid impact, thermal gradients/cycling, and to withstand moonquakes. LINA’s structural design criteria and the resulting structure design are detailed in separate papers. A Fused Filament Fabrication (FFF) construction process using regolith polymer composites has been developed and is detailed in a separate publication. This paper presents material formulations and selection rationale for each of the composite components that were examined. Formulations include 70:30, 80:20, and 85:15 wt.% mixture ratios of lunar mare simulant Black Point-1 (BP-1): Polylactic Acid (PLA), 80:20 Lunar Highlands Simulant-1 (LHS-1): PLA and an 80:20 BP-1: PLA formulation with a flow enhancer additive. Test samples were printed in simulated lunar dirty thermal vacuum conditions (-190 °C, 10-3 torr). A series of tests were performed on each formulation to characterize the achieved mixture ratio, mechanical strength properties, off-gassing products during vacuum printing, and porosity and density of printed products. The LHS-1: PLA formulation yielded an advantageous combination of properties and was used in a final test that additively constructed a sub-scaled LINA on regolith simulant in dirty vacuum conditions. The materials and construction process presented in this paper are considered to be at Technology Readiness Level (TRL) 5 with additional testing necessary to characterize long term lunar environmental exposure effects.

lunar infrastructure↗

DOE OSTI2026

Gravitational Waves as a Source of Large-Scale White Noise: New Constraints

A stochastic gravitational wave (GW) background sources a shear in the flow of cosmic fluid which, through non-linear mode coupling, generates large-scale white noise (LSWN) in the kurvature density field. Building on the LSWN framework of our previous work, we derive the amplitude of this GW-induced LSWN and translate the observational non-detection of LSWN into bounds on the production redshift and density of gravity waves. In particular, a minimal constraint on gravity waves with $z=0$ density parameter $Ω_\mathrm{GW0}^*$ in frequency band $f_*$ generated at redshift $z_*$ must satisfy ${z_*}^2\,Ω_\mathrm{GW0}^*<5\times10^7\,(f_*/\mathrm{nHz})^{3/2}$. This, for example, precludes the gravity waves recently detected by pulsar timing arrays \cite{NANOGrav:2023hvm} from being present before $z_*\sim10^8$, long after the quark hadron phase transition. While orders of magnitude stronger than other constraints on gravity waves, this is a minimal LSWN constraint as realistic modeling of early universe gravity wave production, including the granularity of the gravity-wave sources and the LSWN produced by the associated acoustic waves would probably tighten this constraint by orders of magnitude.

Barenboim, Gabriela [Valencia U., IFIC; Valencia U↗

NASA NTRS2003

Microgravity and Hypogravity Compatible Methods for the Destruction of Solid Wastes by Magnetically Assisted Gasification

This report summarizes a three-year collaborative effort between researchers at UMPQUA Research Company (URC) and the Chemical Engineering Department at Oregon State University (OSU). The Magnetically Assisted Gasification (MAG) concept was originally conceived as a microgravity and hypogravity compatible means for the decomposition of solid waste materials generated aboard spacecraft, lunar and planetary habitations, and for the recovery of potentially valuable resources. While a number of methods such as supercritical water oxidation (SCW0), fluidized bed incineration, pyrolysis , composting and related biological processes have been demonstrated for the decomposition of solid wastes, none of these methods are particularly well- suited for employment under microgravity or hypogravity conditions. For example, fluidized bed incineration relies upon a balance between drag forces which the flowing gas stream exerts upon the fluidization particles and the opposing force of gravity. In the absence of gravity, conventional fluidization cannot take place. Hypogravity operation can also be problematic for conventional fluidized bed reactors, because the various factors which govern fluidization phenomena do not all scale linearly with gravity. For this reason it may be difficult to design and test fluidized bed reactors in lg, which are intended to operate under different gravitational conditions. However, fluidization can be achieved in microgravity (and hypogravity) if a suitable replacement force to counteract the forces between fluid and particles can be found. Possible alternatives include: centripetal force, electric fields, or magnetic fields. Of these, magnetic forces created by the action of magnetic fields and magnetic field gradients upon ferromagnetic media offer the most practical approach. The goal of this URC-OSU collaborative effort was to develop magnetic hardware and methods to control the degree of fluidization (or conversely consolidation) of granular ferromagnetic media and to employ these innovations in sequential filtration and fluidized bed processes for the segregation and decomposition of solid waste materials, and for the concentration and collection of inorganic residue (ash). This required the development of numerous enabling technologies and tools.

Atwater, James E.↗

DOE OSTI2024

Scale-Up Studies for the Dehydration of C 4+ Alcohols into Drop-In Diesel Fuel

Herein, we demonstrate the production of liter quantities of drop-in diesel-range ethers from biomass-derived alcohols. We report scale-up resultsfor the dehydration of a mixture of C 4+ alcohols using powder and pellet zeolite Ycatalyst in continuous flow and batch reactors. The activity of zeolite Y decreaseswith the introduction of an alumina binder. Large alcohols, as well as branchedand secondary alcohols, increase the coke content over the pellet Y catalyst. Thepellet formulation had lower carbon balances and selectivity to C 10+ ethers,suggesting that the pellet formulation increases alcohol absorption and cokeproduction. Crushing the pellet Y catalyst to smaller particle sizes does notrecover the activity of zeolite Y in its powder form. Cold flow experiments showthat particle agglomeration contributes to pressure buildup in the continuous flowreactor. C 10+ ether blends can be produced in batch reactors at high alcohol conversion regimes. One liter of a diesel #2 blend wasproduced by scaling up this reaction. The final blend consists of a substantial portion of C 10+ ethers (63.7 wt %), followed by heavyunknown products (27.4 wt %). Furthermore, the final alcohol and butyl ether concentration values were 7.3 and 1.5 wt %, respectively. Theblendstock reported in this paper can satisfy diesel #2 ASTM standards for density, cloud point, flashpoint, and cetane number.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRSDate not supplied

Charge Deposition/Neutralization and Dust Removal via Plasma Interactions

Electrically charged and chemically reactive lunar dust can cause serious problems to spacecraft, surface equipment, and astronaut health, so understanding its interaction with and transport through the lunar plasma environment is important to dust mitigation efforts. We explore the charging of granular material in the natural environment of the Moon, recreate those conditions in the laboratory under high vacuum, and examine dust transport and charge neutralization for application in future lunar missions. Phenomena such as charge deposition via electron and ion beams, photoionization through ultraviolet light exposure, neutralization of charge through impingement by an ionized compressed gas, and tribocharging during dust liberation from surfaces will be presented. Surface materials of interest such as floating/grounded conductors and orthofabric for spacesuits are the preliminary focus of this effort. An electrometer is used to characterize currents interacting with the surfaces in the case of the electron/ion/UV source exposure, an electrostatic voltmeter is used to measure the potential on the surfaces without inadvertently discharging them, and a charge plate monitor is used to verify the efficiency of discharging the surfaces via ionized gas impingement. After setup of the initial charge conditions on the surfaces, a quick burst of high-pressure gas is used to overcome adhesion forces and initially dislodge the dust from the surfaces, followed by a low flow of gas that is ionized via application of a strong electric field. The gas is released in a high vacuum environment so as the pressure drops from the initial compressed state through to the vacuum state, the mean free path reaches a point where ionization can occur before all the gas disperses into the vacuum. This ionized gas can then neutralize both the dust and the surface to ensure minimal resettling. Several parameters such as gas composition, electrode geometry, high voltage waveform shape/polarity, and pulse timing have been explored and will be presented here.

electrostatics↗

NASA NTRS2024

Interim Measures Work Plan: South Repeater Building: Solid Waste Management Unit 121: Hydraulic Containment and Groundwater Treatment System for Per- and Polyfluoroalkyl Substances: Kennedy Space Center, Florida

This document presents the design details of a granular activated carbon (GAC) hydraulic containment and groundwater treatment system Interim Measures Work Plan for the South Repeater Building site (South Repeater, Solid Waste Management Unit 121), located at John F. Kennedy Space Center (KSC), Florida. The interim measures (IM) treatment area includes the source area and downgradient property boundary, which have been impacted by per- and polyfluoroalkyl substances (PFAS). The objectives of the IM are to treat the source area and mitigate PFAS migration to areas outside of KSC boundaries. This document was prepared by AECOM Technical Services, Inc., for the National Aeronautics and Space Administration under Contract 80KSC019D0010, Task Order 80KSC021F0096. The IM consists of the installation and operation of 19 extraction wells and an associated groundwater treatment system. A total of 13 wells will be installed to a depth of 34 feet below land surface (bls) to target the upper medium-grained sand with shell layer. A total of six wells will be installed to a depth of 56 feet bls to target the lower layer of poorly graded sand with shell fragments. The system will be designed to operate each extraction well simultaneously using submersible pumps at flow rates of 5 or 10 gallons per minute (gpm), excluding one extraction well with a flow rate of 30 gpm. The extracted groundwater will be conveyed to a groundwater treatment system, where it will be treated via GAC prior to disposal via infiltration. To evaluate treatment system performance, baseline groundwater sampling will be conducted prior to treatment system startup. Performance monitoring will be completed quarterly for the first year. A total of eight performance monitoring wells will be installed to a depth of 12 feet bls, and eight performance monitoring wells will be installed to a depth of 30 feet bls. In addition to the installation of 16 performance monitoring wells, 12 existing monitoring wells will be incorporated into the performance monitoring program.

groundwater treatment↗

NASA NTRS2021

Analytical Methods and Testbeds for Characterizing Adsorbents and Catalysts for Atmosphere Revitalization of Crewed Spacecraft

Spacecraft environmental control and life support systems (ECLSS) include a number of air revitalization (AR) technologies to provide breathable air and a comfortable living environment to the crew. Crew health and comfort is ensured by controlling human produced CO2 (1 kg person-1 day-1) and water vapor (~2 kg person-1 day-1), and by removing trace contaminants (TCs) from cabin air. These life support functions on-board the International Space Station (ISS) are carried out by the Carbon Dioxide Removal Assembly (CDRA), the Water Processor Assembly (WPA), and the trace contaminant control system (TCCS). During the development of the TCCS, new analytical and theoretical methods were developed in the 1970s for characterizing adsorption and desorption characteristics of activated carbons for the purpose of designing suitable AR technologies required for controlling airborne trace contaminants within spacecraft cabins during long exploration missions. The TCCS removes harmful volatile organic compounds and other trace contaminants from the circulating air. It consists of a granular activated carbon (GAC) bed for the removal of high molecular weight contaminants and ammonia followed by a heated catalytic bed for low molecular weight hydrocarbons. The high temperature catalytic oxidizer (HTCO) of the TCCS, which operates at 400°C and requires 120W average power, removes low molecular weight compounds such as carbon monoxide (CO), formaldehyde (CH2O), and methane (CH4), that pass through the GAC bed. The Air Revitalization Laboratory at the Kennedy Space Center (KSC) was established to develop new analytical methods for evaluating emerging ECLSS technologies for use in future AR architectures. General properties of adsorbents and catalysts are required for trace contaminant control system design calculations and vendor-supplied data are seldom available at relevant process conditions of interest to spacecraft cabin applications. To address this shortcoming, appropriate testbeds were developed to measure the desired properties of AR technologies being considered for use in ECLS architectures. Generally, the testbeds developed at KSC challenge the test media (activated carbon, impregnated activated carbon, catalysts, zeolites, solid amines, or pleated filters) with simulated spacecraft gas streams containing representative mixtures of trace contaminants (volatile organic compounds, ammonia, CO, CO2, or siloxanes) at the flow rates, temperatures, and relative humidity that will be encountered within manned spacecraft. Work performed at KSC funded by NASA’s Advanced Exploration (AES) Program has included: Identifying candidate sorbents to replace commercially obsolete impregnated carbons for NH3 control within the TCCS, characterizing their adsorptive capacities using simulated spacecraft gas streams, and ranking their appropriateness in various AR applications; evaluating novel low temperature catalysts for controlling CO and formaldehyde by traditional and photocatalytic methods for trace contaminant control; development of analytical methods to assess regenerable solid amine performance for CO2 control via pressure swing adsorption. The Air Revitalization lab was also funded to study trace contaminant control by other NASA programs. These include: screening of candidate sorbents for the design of new Charcoal HEPA Integrated Particle Scrubber (CHIPS) filters for removing siloxanes from cabin air; characterizing the performance of an impregnated activated carbon at low humidity for use in ORION ECLS; screening of sorbents for protecting the Sabatier 2.0 catalyst from DMSO2, siloxanes, NH3, and solid amine byproducts.

Monje, Oscar↗

DOE OSTI2026

Characterizing radial flow fluctuations in relativistic heavy-ion collisions at top RHIC and LHC energies

This study presents a systematic investigation of the transverse-momentum differential radial flow fluctuations observable 𝑣 0 ⁡ (𝑝 𝑇 ) in relativistic heavy-ion collisions at top Relativistic Heavy Ion Collider ($\sqrt{s_{NN}}$ = 200 GeV) and Large Hadron Collider ($\sqrt{s_{NN}}$ = 2.76 and 5.02 TeV) energies. Using a multistage hydrodynamic model, this study assesses the sensitivity of 𝑣 0 ⁡(𝑝 𝑇 ) to a wide range of physical effects, including bulk and shear viscosities, off-equilibrium corrections at particlization, the presence of a hadronic afterburner, and the nucleon size in the initial conditions. By employing complementary rescaling strategies, this study demonstrates how different physical effects leave distinct imprints on the shape of 𝑣 0 ⁡(𝑝 𝑇 ). A combined double-rescaling of 𝑣 0 ⁡(𝑝 𝑇 )/𝑣 0 versus 𝑝 𝑇 /⟨𝑝 𝑇 ⟩ reveals a universality across a wide range of energies and model assumptions in the low-𝑝 𝑇 regime, a robust signature of collective behavior. This allows us to disentangle the universal dynamics of the bulk medium from model-specific features that emerge at higher 𝑝 𝑇 . These results establish 𝑣 0⁡ (𝑝 𝑇 ) as a powerful and complementary observable for constraining quark-gluon plasma transport properties and initial-state granularity, offering a unique probe of the created QCD medium.

Du, Lipei [University of California, Berkeley, CA ↗

NASA NTRS1999

MRI Measurements and Granular Dynamics Simulation of Segregation of Granular Mixture

A counter intuitive axial segregation phenomenon in a rotating horizontal cylinder has recently captured attention of many researchers in different disciplines. There is a growing consensus that the interplay between the particle dynamics and the evolution of the internal structure during the segregation process must be carefully investigated. Magnetic resonance imaging (MRI) has been used to non-invasively obtain much needed dynamic/static information such as velocity and concentration profiles, and it has proven to be capable of depicting the evolution of segregation processes. Segregation in a rotating cylinder involves two processes: the first is to transport small particles in the radial direction to form a radial core, and the second is to transform the radial core into axially segregated bands. Percolation and/or "stopping" have been proposed as mechanisms for the radial segregation. As to mechanisms for axial band formation, much less is known. The difference in the dynamic angle of repose has been proposed to segregate different components in the axial direction. Recently, Hill and Kakalios have reported that particles mix or demix depending upon the competition between diffusion and preferential drift whose order can be determined by the dynamic angle of repose through the adjustment of the rotation rate. We claim that the dynamic angle of repose could be one of the causes, however, it fails to offer reasonable explanations for certain aspects of the axial migration. For example, we always observe that the radial segregation precedes the axial segregation and small particles migrate in the radial direction to form an axially extended radial core. It then transforms into axially segregated bands. By definition, the effects of the dynamic angle of repose are restricted near the free surface where the flowing layer is present. However, during the process of transforming from the radially segregated core to axially segregated bands, small particles located in the deep core region, which is untouched by the flowing layer, also completely disappear. Usually, the dynamics angle of repose are uniquely defined for individual species to characterize particle properties, and the dynamic angle of repose thus defined provides little information for the dynamic angle of repose of the mixture since the concentration ratio and the internal packing structure do not remain the same during the segregation processes. Under microgravity environment, the dynamics angle of repose argument does not hold since there is simply no flowing layer to influence/determine the preferred directions of segregation. We have thus designed an experiment so that the effects of the dynamic angle of repose can be minimized by filling the cylinder almost completely full. Small particles still formed a radial core and also migrated to form axial bands. As ground based experiments we have designed and conducted both 2D and 3D segregation experiments. The 2D experiments are performed using a thin cylinder (the gap between two end caps is about 5 mm) filled with different combinations of particles. The 3D experiments are conducted with a long cylinder of its length and diameter of 27cm and 7cm, respectively. Results of 2D experiments indicate that different mechanisms govern particle motion in regions near and far from the axis of rotation. Results of 3D experiments indicate that a series of collapses of microstructures of particle packing (micro-collapses) may be responsible for the creation of voids for small particles to migrate through in the axial direction. We have successfully eliminated the dynamic angle of repose as a cause for segregation, however, by almost completely filling the cylinder with the particles, we have lost an opportunity to investigate a possibility of particle "mobility" being a cause for segregation which requires a flowing surface but not the difference in the angle of repose. This is currently being investigated.

Nakagawa, M.↗

NASA NTRS2001

Viscoplastic Model Development to Account for Strength Differential: Application to Aged Inconel 718 at Elevated Temperature

The magnitude of yield and flow stresses in aged Inconel 718 are observed to be different in tension and compression. This phenomenon, called the Strength differential (SD), contradicts the metal plasticity axiom that the second deviatoric stress invariant alone is sufficient for representing yield and flow. Apparently, at least one of the other two stress invariants is also significant. A unified viscoplastic model was developed that is able to account for the SD effect in aged Inconel 718. Building this model involved both theory and experiments. First, a general threshold function was proposed that depends on all three stress invariants and then the flow and evolution laws were developed using a potential-based thermodynamic framework. Judiciously chosen shear and axial tests were conducted to characterize the material. Shear tests involved monotonic loading, relaxation, and creep tests with different loading rates and load levels. The axial tests were tension and compression tests that resulted in sufficiently large inelastic strains. All tests were performed at 650 C. The viscoplastic material parameters were determined by optimizing the fit to the shear tests, during which the first and the third stress invariants remained zero. The threshold surface parameters were then fit to the tension and compression test data. An experimental procedure was established to quantify the effect of each stress invariant on inelastic deformation. This requires conducting tests with nonproportional three-dimensional load paths. Validation of the model was done using biaxial tests on tubular specimens of aged Inconel 718 using proportional and nonproportional axial-torsion loading. These biaxial tests also helped to determine the most appropriate form of the threshold function; that is, how to combine the stress invariants. Of the set of trial threshold functions, the ones that incorporated the third stress invariant give the best predictions. However, inclusion of the first stress invariant does not significantly improve the model predictions. The model shows excellent predictive capability for nonproportional load paths. Additionally, it reduces to the well-known models of Mises Drucker and Drucker-Prager. The requisite experiments involve reasonably simple load paths in the axial-shear stress plane and hence can be performed on a variety of different materials: be they metallic, geological. polymeric, ceramic or granular. The general form of the threshold function allows representation of inelastic deformation in a range of materials.

Iyer, Saiganesh↗

NASA NTRS2002

Uses of Computed Tomography in the NASA Materials Science Program

Computed Tomography (CT) has proved to be of inestimable use in providing a rapid evaluation of a variety of samples from Mechanics of Granular Materials (MGM) to electronic materials (Ge-Si alloys) to space grown materials such as meteorites. The system at Kennedy Space Center (KSC), because of its convenient geographical location, is ideal for examining samples immediately after returning to Earth. It also has the advantage of the choice of fluxes, and in particular the use of a radioactive cobalt source, which is basically monochromatic. This permits a reasonable measurement of density to be made from which chemical composition can be determined. Due to the current dearth of long duration space grown materials, the CT instrument has been used to characterize materials in preparation for flight, to determine thermal expansion values, and to examine long duration space grown materials, i.e. meteorites. The work will first describe the establishment of the protocol for obtaining the optimum density readings for any material. This will include both the effects of the hardware or instrumental parameters that can be controlled, and the techniques used to process the CT data. Examples will be given of the compositional variation along single crystals of germanium-silicon alloys. Density variation with temperature has been measured in preparation for future materials science experiments; this involved the fabrication and installation of a single zone furnace incorporating a heat pipe to ensure of high temperature uniformity. At the time of writing the thermal expansion of lead has been measured from room temperature to 900 C. Three methods are available. Digital radiography enable length changes to be determined. Prior to melting the sample is small than the container and the diameter change can be measured. Most critical, however, is the density change in solid, through the melting region, and in the liquid state. These data are needed for engineering purposes to aid in the design of containment cartridges, and for enabling fluid flow calculations. A second sample, with the lead alloyed with antimony is ready for scanning. This corresponds to the planned composition of Dr. Poirier's flight experiment. Finally, three-dimensional results will be shown of the structure of a two-phase metallic meteorite of metal and sulfide, in which the iron-nickel phase has coarsened during slow cooling over hundreds of millions of years.

Engel, H. Peter↗

NASA NTRS2003

Uses of Computed Tomography for Characterizing Materials Grown Terrestrially and in Microgravity

Tomography (CT) has proved to be of inestimable use in providing a rapid evaluation of a variety of samples from Mechanics of Granular Materials (MGM) to electronic materials (Ge-Si alloys) to space grown materials such as meteorites. The system at Kennedy Space Center (KSC), because of its convenient geographical location, is ideal for examining samples before launch and immediately after returning to Earth. It also has the advantage of the choice of fluxes, and in particular the use of a radioactive cobalt source, which is basically monochromatic. This permits a reasonable measurement of density to be made from which chemical composition can be determined. Due to the current dearth of long duration space grown materials, the CT instrument has been used: (1) to characterize materials in preparation for flight, (2) to determine thermal expansion values, and (3) to examine long duration space grown materials, i.e. meteorites. This work will first describe the establishment of the protocol for obtaining the optimum density readings for any material. Included will be the effects of the hardware or instrumental parameters that can be controlled, and the techniques used to process the CT data. Examples will be given of the compositional variation along a single crystal of Ge-Si alloy. Density variation with temperature has been measured in preparation for future materials science experiments; this involved the fabrication at MSFC and installation of a single zone furnace at KSC incorporating a heat pipe to ensure high temperature uniformity. At the time of writing the thermal expansion of lead (Pb) has been measured from room temperature to 900 C. Three methods are available. Digital radiography enables length changes to be determined. Prior to melting the sample is smaller than the container and the diameter change can be measured. Most critical, however, is the density change in solid, through the melting region, and in the liquid state. These data are needed for engineering purposes to aid in the design of containment cartridges, and for enabling fluid flow calculations. A second sample, with the Pb alloyed with Sb is ready for scanning. This corresponds to the planned composition of Dr. Poirier s flight experiment. Other materials pertinent to NASA programs such as Al-Cu (Trivedi), CdTe (Banish), HgCdTe (Lehoczky) will be examined below and above the melting point. Finally, three-dimensional results will be shown of the structure of a two-phase metallic meteorite of metal and sulfide, in which the Fe-Ni phase has coarsened during slow cooling over hundreds of millions of years.

Source record↗

NASA NTRS2011

Experimental Testing and Modeling of a Pneumatic Regolith Delivery System for ISRU

Excavating and transporting planetary regolith are examples of surface activities that may occur during a future space exploration mission to a planetary body. Regolith, whether it is collected on the Moon, Mars or even an asteroid, consists of granular minerals, some of which have been identified to be viable resources that can be mined and processed chemically to extract useful by-products, such as oxygen, water, and various metals and metal alloys. Even the depleted "waste" material from such chemical processes may be utilized later in the construction of landing pads and protective structures at the site of a planetary base. One reason for excavating and conveying planetary regolith is to deliver raw regolith material to in-situ resource utilization (ISRU) systems. The goal of ISRU is to provide expendable supplies and materials at the planetary destination, if possible. An in-situ capability of producing mission-critical substances such as oxygen will help to extend the mission and its success, and will greatly lower the overall cost of a mission by either eliminating, or significantly reducing, the need to transport the same expendable materials from the Earth. In order to support the goals and objectives of present and future ISRU projects, NASA seeks technology advancements in the areas of regolith conveying. Such systems must be effective, efficient and provide reliable performance over long durations while being exposed to the harsh environments found on planetary surfaces. These conditions include contact with very abrasive regolith particulates, exposure to high vacuum or dry (partial) atmospheres, wide variations in temperature, reduced gravity, and exposure to space radiation. Regolith conveying techniques that combine reduced failure modes and low energy consumption with high material transfer rates will provide significant value for future space exploration missions to the surfaces of the moon, Mars and asteroids. Pneumatic regolith conveying has demonstrated itself to be a viable delivery system through testing under terrestrial and reduced gravity conditions in recent years. Modeling and experimental testing have been conducted at NASA Kennedy Space Center to study and advance pneumatic planetary regolith delivery systems in support of NASA's ISRU project. The goal of this work is to use the model to predict solid-gas flow patterns in reduced gravity environments for ISRU inlet gas line allowing the eductor inlet gas flow to vary and depend on the flow pattern developed at the eductor as inferred by the experimental observations.

Santiago-Maldonado, Edgardo↗